ΔE 10.9, fair: the same colour family, but not a straight swap. IJN Gray (Kure Arsenal) is a little darker, more muted, warmer than Stormfang.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). IJN Gray (Kure Arsenal) is a little darker, more muted, warmer than Stormfang.
The same difference applies the other way round: Stormfang is a little lighter, more saturated, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Stormfang on the colour wheel See IJN Gray (Kure Arsenal) on the colour wheel
All matches: Stormfang equivalents · IJN Gray (Kure Arsenal) equivalents